Singer D, Steffens A, La E, Horn EK, Theiss-Nyland K, Fonseca MJ, Gerber S, Kawai A, Buikema A, Johnson MG, Song R, Hague S, Layton JB. Adjuvanted RSVPreF3 vaccine effectiveness against RSV-related hospitalization among US adults aged 60 years and older. Poster presented at the ReSViNET 2026; February 17, 2026. Rome, Italy.

OBJECTIVE: This study evaluated the real-world effectiveness of adjuvanted RSVPreF3 vaccination for the prevention of respiratory syncytial virus (RSV)-related hospitalization among adults aged ≥60 years in the United States (US).

BACKGROUND: Previous observational studies have reported the real-world effectiveness of adjuvanted RSVPreF3 vaccination against RSV-related hospitalizations among older adults; however, additional evidence is needed to inform RSV vaccination efforts and address remaining evidence gaps (e.g., evaluating vaccine effectiveness [VE] in subgroups at increased risk for severe RSV disease).

METHODS: A retrospective cohort study was conducted using administrative claims data from the Optum Research Database (ORD; August 2022–May 2024) to evaluate the VE of adjuvanted RSVPreF3 against RSV-related hospitalization (defined by International Classification of Diseases, Tenth Revision, Clinical Modification diagnosis codes for RSV). Adults aged ≥60 years were identified between August 2023–May 2024. Vaccinated and unvaccinated patients were exact matched 1:4 by age, sex, insurance type, and state of residence, with index date assigned as the vaccination date. Baseline characteristics were measured during the 12-month pre-index period in which continuous enrollment was required. Patients were followed from 14 days post-index date to the earliest of the following: disenrollment, death, RSV vaccination, or end of the analysis period. Propensity score-based weighting was used to balance characteristics not included in matching. After weighting, hazard ratios were estimated using Cox proportional hazards regression in the overall population and in subgroups of interest. VE was calculated as (1 − hazard ratio) x 100%.

RESULTS: A total of 520,440 vaccinated and 2,081,760 unvaccinated individuals were included in the analysis, with 56.9% female, mean (standard deviation) age of 74.3 (6.7) years and Charlson Comorbidity Index of 1.4 (1.8). Median follow-up was 5 months, with a maximum of 10 months. Estimated VE was 75.6% (95% confidence interval [CI]: 69.8%–80.2%). VE estimates in subgroups of interest included 72.5% (95% CI: 64.3%–78.8%) among those with chronic pulmonary disease, 72.2% (95% CI: 64.1%–78.4%) among those with cardiovascular disease, 82.3% (95% CI: 74.2%–87.9%) among those with diabetes, and 71.4% (95% CI: 57.0%–81.1%) among those who were immunocompromised.

CONCLUSIONS: These findings add to the body of real-world evidence highlighting the effectiveness of adjuvanted RSVPreF3 vaccination in preventing RSV-related hospitalization among adults aged ≥60 years, including those at risk due to comorbidities, suggesting that vaccination is an effective strategy in reducing disease burden.